A novel nickel(II) complex obtained from 2-[(3-bromo-propylimino)-methyl]-phenol as a ligand: synthesis, structural characterization, electrochemical and electrocatalytical investigations

Abstract

Herein, we describe the synthesis of novel bidentate Schiff base ligand 2-[(3-bromo-propylimino)-methyl]-phenol (HL) and its Ni(II) complex in 2:1 (ligand:metal) ratio. The synthesized ligand (HL) and its Ni(II) complex were characterized using routine spectroscopic techniques like microanalysis, UV–visible absorption spectroscopy, FT-IR, NMR (1H and 13C). A suitable single crystal of the nickel complex was obtained from acetone solution by slow evaporation and studied by X-ray diffraction to determine its molecular structure. The crystallographic data of the obtained Ni(II)-2L complex revealed that it possesses a monoclinic space group P 21/n with cell dimensions of a = 10.6818(2) Å, b = 7.1071(1) Å, c = 13.7925(3) Å, β = 105.51(1)°, Z = 4. The electrochemical investigation of both ligand and its Ni(II)-2L complex was carried out by cyclic voltammetry. The cyclovoltammograms showed two redox systems, Ni(II)/Ni(I) and Ni(III)/Ni(II). Interestingly, it was revealed that the Ni(II)-2L complex can be polymerized into its poly-[Ni(II)-2L] films, and electrodeposited onto glassy carbon. The resulting Ni(II)/Ni(I) and Ni(III)/Ni(II) redox systems were advantageously used. The first one was used in the electroreduction of bromocyclopentane while the second one Ni(III)/Ni(II) is rather applied to oxidize methanol.